1 | /** |
---|
2 | * @file rtems/score/heap.h |
---|
3 | * |
---|
4 | * This include file contains the information pertaining to the Heap |
---|
5 | * Handler. A heap is a doubly linked list of variable size |
---|
6 | * blocks which are allocated using the first fit method. Garbage |
---|
7 | * collection is performed each time a block is returned to the heap by |
---|
8 | * coalescing neighbor blocks. Control information for both allocated |
---|
9 | * and unallocated blocks is contained in the heap space. A heap control |
---|
10 | * structure contains control information for the heap. |
---|
11 | * |
---|
12 | * FIXME: the alignment routines could be made faster should we require only |
---|
13 | * powers of two to be supported both for 'page_size' and for |
---|
14 | * 'alignment' arguments. However, both workspace and malloc heaps are |
---|
15 | * initialized with CPU_HEAP_ALIGNMENT as 'page_size', and while all |
---|
16 | * the BSPs seem to use CPU_ALIGNMENT (that is power of two) as |
---|
17 | * CPU_HEAP_ALIGNMENT, for whatever reason CPU_HEAP_ALIGNMENT is only |
---|
18 | * required to be multiple of CPU_ALIGNMENT and explicitly not |
---|
19 | * required to be a power of two. |
---|
20 | * |
---|
21 | * COPYRIGHT (c) 1989-2006. |
---|
22 | * On-Line Applications Research Corporation (OAR). |
---|
23 | * |
---|
24 | * The license and distribution terms for this file may be |
---|
25 | * found in the file LICENSE in this distribution or at |
---|
26 | * http://www.rtems.com/license/LICENSE. |
---|
27 | * |
---|
28 | * $Id$ |
---|
29 | */ |
---|
30 | |
---|
31 | #ifndef _RTEMS_SCORE_HEAP_H |
---|
32 | #define _RTEMS_SCORE_HEAP_H |
---|
33 | |
---|
34 | /** |
---|
35 | * @defgroup ScoreHeap Heap Handler |
---|
36 | * |
---|
37 | * This handler encapsulates functionality which provides the foundation |
---|
38 | * Heap services used in all of the APIs supported by RTEMS. |
---|
39 | */ |
---|
40 | /**@{*/ |
---|
41 | |
---|
42 | #ifdef __cplusplus |
---|
43 | extern "C" { |
---|
44 | #endif |
---|
45 | |
---|
46 | /** |
---|
47 | * This type defines unsigned integer type to store 'void*'. Analog of C99 |
---|
48 | * 'uintptr_t'. This should work on 16/32/64 bit architectures. |
---|
49 | * |
---|
50 | * FIXME: Something like this should better be defined by |
---|
51 | * 'rtems/score/types.h' and used here. |
---|
52 | */ |
---|
53 | |
---|
54 | typedef uintptr_t _H_uptr_t; |
---|
55 | |
---|
56 | /** |
---|
57 | * Forward reference |
---|
58 | * |
---|
59 | * @ref Heap_Block |
---|
60 | */ |
---|
61 | typedef struct Heap_Block_struct Heap_Block; |
---|
62 | |
---|
63 | /** |
---|
64 | * The following defines the data structure used to manage individual blocks |
---|
65 | * in a heap. When the block is allocated, the 'next' and 'prev' fields, as |
---|
66 | * well as 'prev_size' field of the next block, are not used by the heap |
---|
67 | * manager and thus the address returned for the block starts at the address |
---|
68 | * of the 'next' field and the size of the user accessible area includes the |
---|
69 | * size of the 'prev_size' field. |
---|
70 | * |
---|
71 | * @note The 'next' and 'prev' pointers are only valid when the block is free. |
---|
72 | * Caution must be taken to ensure that every block is large enough to |
---|
73 | * hold them and that they are not accessed while the block is actually |
---|
74 | * allocated (i.e., not free). |
---|
75 | * |
---|
76 | * @note The 'prev_size' field is only valid when HEAP_PREV_USED bit is clear |
---|
77 | * in the 'size' field indicating that previous block is not allocated. |
---|
78 | * If the bit is set, the 'prev_size' field is part of user-accessible |
---|
79 | * space of the previous allocated block and thus shouldn't be accessed |
---|
80 | * by the heap manager code. This trick allows to further decrease |
---|
81 | * overhead in the used blocks to the size of 'size' field (4 bytes). |
---|
82 | * |
---|
83 | */ |
---|
84 | |
---|
85 | struct Heap_Block_struct { |
---|
86 | /** size of prev block (if prev block is free) */ |
---|
87 | uint32_t prev_size; |
---|
88 | /** size of block in bytes and status of prev block */ |
---|
89 | uint32_t size; |
---|
90 | /** pointer to the next free block */ |
---|
91 | Heap_Block *next; |
---|
92 | /** pointer to the previous free block */ |
---|
93 | Heap_Block *prev; |
---|
94 | }; |
---|
95 | |
---|
96 | /** |
---|
97 | * This flag used in the 'size' field of each heap block to indicate |
---|
98 | * if previous block is free or in use. As sizes are always multiples of |
---|
99 | * 4, the 2 least significant bits would always be 0, and we use one of them |
---|
100 | * to store the flag. |
---|
101 | */ |
---|
102 | |
---|
103 | #define HEAP_PREV_USED 1 /* indicates previous block is in use */ |
---|
104 | |
---|
105 | /** |
---|
106 | * The following constants reflect various requirements of the |
---|
107 | * heap data structures which impact the management of a heap. |
---|
108 | */ |
---|
109 | |
---|
110 | #define HEAP_MIN_BLOCK_SIZE (sizeof(Heap_Block)) |
---|
111 | |
---|
112 | /** |
---|
113 | * Offset of the block header from the block pointer. Equal to the |
---|
114 | * offsetof(Heap_Block.size). |
---|
115 | */ |
---|
116 | #define HEAP_BLOCK_HEADER_OFFSET (sizeof(uint32_t)) |
---|
117 | |
---|
118 | /** |
---|
119 | * Offset of user data pointer from the block pointer. Equal to the |
---|
120 | * offsetof(Heap_Block.next). |
---|
121 | */ |
---|
122 | #define HEAP_BLOCK_USER_OFFSET (sizeof(uint32_t) * 2) |
---|
123 | |
---|
124 | /** |
---|
125 | * Num bytes of overhead in used block. Equal to the sizeof(Heap_Block.size). |
---|
126 | */ |
---|
127 | #define HEAP_BLOCK_USED_OVERHEAD \ |
---|
128 | (HEAP_BLOCK_USER_OFFSET - HEAP_BLOCK_HEADER_OFFSET) |
---|
129 | |
---|
130 | /** Size of the permanent dummy last block. */ |
---|
131 | #define HEAP_OVERHEAD HEAP_BLOCK_USER_OFFSET |
---|
132 | |
---|
133 | /** |
---|
134 | * Run-time heap statistics. |
---|
135 | * |
---|
136 | * @note (double)searches/allocs gives mean number of searches per alloc while |
---|
137 | * max_search gives maximum number of searches ever performed on a |
---|
138 | * single call to alloc. |
---|
139 | * |
---|
140 | * @note the statistics is always gathered. I believe the imposed overhead is |
---|
141 | * rather small. Feel free to make it compile-time option if you think |
---|
142 | * the overhead is too high for your application. |
---|
143 | */ |
---|
144 | |
---|
145 | typedef struct Heap_Statistics_tag { |
---|
146 | /** instance number of this heap */ |
---|
147 | uint32_t instance; |
---|
148 | /** the size of the memory for heap */ |
---|
149 | uint32_t size; |
---|
150 | /** current free size */ |
---|
151 | uint32_t free_size; |
---|
152 | /** minimum free size ever */ |
---|
153 | uint32_t min_free_size; |
---|
154 | /** current number of free blocks */ |
---|
155 | uint32_t free_blocks; |
---|
156 | /** maximum number of free blocks ever */ |
---|
157 | uint32_t max_free_blocks; |
---|
158 | /** current number of used blocks */ |
---|
159 | uint32_t used_blocks; |
---|
160 | /** maximum number of blocks searched ever */ |
---|
161 | uint32_t max_search; |
---|
162 | /** total number of successful calls to alloc */ |
---|
163 | uint32_t allocs; |
---|
164 | /** total number of searches ever */ |
---|
165 | uint32_t searches; |
---|
166 | /** total number of suceessful calls to free */ |
---|
167 | uint32_t frees; |
---|
168 | /** total number of successful resizes */ |
---|
169 | uint32_t resizes; |
---|
170 | } Heap_Statistics; |
---|
171 | |
---|
172 | /** |
---|
173 | * Control block used to manage each heap. |
---|
174 | */ |
---|
175 | typedef struct { |
---|
176 | /** head and tail of circular list of free blocks */ |
---|
177 | Heap_Block free_list; |
---|
178 | /** allocation unit and alignment */ |
---|
179 | uint32_t page_size; |
---|
180 | /** minimum block size aligned on page_size */ |
---|
181 | uint32_t min_block_size; |
---|
182 | /** first address of memory for the heap */ |
---|
183 | void *begin; |
---|
184 | /** first address past end of memory for the heap */ |
---|
185 | void *end; |
---|
186 | /** first valid block address in the heap */ |
---|
187 | Heap_Block *start; |
---|
188 | /** last valid block address in the heap */ |
---|
189 | Heap_Block *final; |
---|
190 | /** run-time statistics */ |
---|
191 | Heap_Statistics stats; |
---|
192 | } Heap_Control; |
---|
193 | |
---|
194 | /** |
---|
195 | * Status codes for _Heap_Extend |
---|
196 | */ |
---|
197 | |
---|
198 | typedef enum { |
---|
199 | HEAP_EXTEND_SUCCESSFUL, |
---|
200 | HEAP_EXTEND_ERROR, |
---|
201 | HEAP_EXTEND_NOT_IMPLEMENTED |
---|
202 | } Heap_Extend_status; |
---|
203 | |
---|
204 | /** |
---|
205 | * Status codes for _Heap_Resize_block |
---|
206 | */ |
---|
207 | |
---|
208 | typedef enum { |
---|
209 | HEAP_RESIZE_SUCCESSFUL, |
---|
210 | HEAP_RESIZE_UNSATISFIED, |
---|
211 | HEAP_RESIZE_FATAL_ERROR |
---|
212 | } Heap_Resize_status; |
---|
213 | |
---|
214 | /** |
---|
215 | * Status codes for _Heap_Get_information |
---|
216 | */ |
---|
217 | |
---|
218 | typedef enum { |
---|
219 | HEAP_GET_INFORMATION_SUCCESSFUL = 0, |
---|
220 | HEAP_GET_INFORMATION_BLOCK_ERROR |
---|
221 | } Heap_Get_information_status; |
---|
222 | |
---|
223 | /** |
---|
224 | * Information block returned by the Heap routines used to |
---|
225 | * obtain heap information. This information is returned about |
---|
226 | * either free or used blocks. |
---|
227 | */ |
---|
228 | typedef struct { |
---|
229 | /** Number of blocks of this type. */ |
---|
230 | uint32_t number; |
---|
231 | /** Largest blocks of this type. */ |
---|
232 | uint32_t largest; |
---|
233 | /** Total size of the blocks of this type. */ |
---|
234 | uint32_t total; |
---|
235 | } Heap_Information; |
---|
236 | |
---|
237 | /** |
---|
238 | * Information block returned by _Heap_Get_information |
---|
239 | */ |
---|
240 | typedef struct { |
---|
241 | /** This field is information on the used blocks in the heap. */ |
---|
242 | Heap_Information Free; |
---|
243 | /** This field is information on the used blocks in the heap. */ |
---|
244 | Heap_Information Used; |
---|
245 | } Heap_Information_block; |
---|
246 | |
---|
247 | /** |
---|
248 | * This routine initializes @a the_heap record to manage the |
---|
249 | * contiguous heap of @a size bytes which starts at @a starting_address. |
---|
250 | * Blocks of memory are allocated from the heap in multiples of |
---|
251 | * @a page_size byte units. If @a page_size is 0 or is not multiple of |
---|
252 | * CPU_ALIGNMENT, it's aligned up to the nearest CPU_ALIGNMENT boundary. |
---|
253 | * |
---|
254 | * @param[in] the_heap is the heap to operate upon |
---|
255 | * @param[in] starting_address is the starting address of the memory for |
---|
256 | * the heap |
---|
257 | * @param[in] size is the size in bytes of the memory area for the heap |
---|
258 | * @param[in] page_size is the size in bytes of the allocation unit |
---|
259 | * |
---|
260 | * @return This method returns the maximum memory available. If |
---|
261 | * unsuccessful, 0 will be returned. |
---|
262 | */ |
---|
263 | uint32_t _Heap_Initialize( |
---|
264 | Heap_Control *the_heap, |
---|
265 | void *starting_address, |
---|
266 | size_t size, |
---|
267 | uint32_t page_size |
---|
268 | ); |
---|
269 | |
---|
270 | /** |
---|
271 | * This routine grows @a the_heap memory area using the size bytes which |
---|
272 | * begin at @a starting_address. |
---|
273 | * |
---|
274 | * @param[in] the_heap is the heap to operate upon |
---|
275 | * @param[in] starting_address is the starting address of the memory |
---|
276 | * to add to the heap |
---|
277 | * @param[in] size is the size in bytes of the memory area to add |
---|
278 | * @param[in] amount_extended points to a user area to return the |
---|
279 | * @return a status indicating success or the reason for failure |
---|
280 | * @return *size filled in with the amount of memory added to the heap |
---|
281 | */ |
---|
282 | Heap_Extend_status _Heap_Extend( |
---|
283 | Heap_Control *the_heap, |
---|
284 | void *starting_address, |
---|
285 | size_t size, |
---|
286 | uint32_t *amount_extended |
---|
287 | ); |
---|
288 | |
---|
289 | /** |
---|
290 | * This function attempts to allocate a block of @a size bytes from |
---|
291 | * @a the_heap. If insufficient memory is free in @a the_heap to allocate |
---|
292 | * a block of the requested size, then NULL is returned. |
---|
293 | * |
---|
294 | * @param[in] the_heap is the heap to operate upon |
---|
295 | * @param[in] size is the amount of memory to allocate in bytes |
---|
296 | * @return NULL if unsuccessful and a pointer to the block if successful |
---|
297 | */ |
---|
298 | void *_Heap_Allocate( |
---|
299 | Heap_Control *the_heap, |
---|
300 | size_t size |
---|
301 | ); |
---|
302 | |
---|
303 | /** |
---|
304 | * This function attempts to allocate a memory block of @a size bytes from |
---|
305 | * @a the_heap so that the start of the user memory is aligned on the |
---|
306 | * @a alignment boundary. If @a alignment is 0, it is set to CPU_ALIGNMENT. |
---|
307 | * Any other value of @a alignment is taken "as is", i.e., even odd |
---|
308 | * alignments are possible. |
---|
309 | * Returns pointer to the start of the memory block if success, NULL if |
---|
310 | * failure. |
---|
311 | * |
---|
312 | * @param[in] the_heap is the heap to operate upon |
---|
313 | * @param[in] size is the amount of memory to allocate in bytes |
---|
314 | * @param[in] alignment the required alignment |
---|
315 | * @return NULL if unsuccessful and a pointer to the block if successful |
---|
316 | */ |
---|
317 | void *_Heap_Allocate_aligned( |
---|
318 | Heap_Control *the_heap, |
---|
319 | size_t size, |
---|
320 | uint32_t alignment |
---|
321 | ); |
---|
322 | |
---|
323 | /** |
---|
324 | * This function sets @a *size to the size of the block of user memory |
---|
325 | * which begins at @a starting_address. The size returned in @a *size could |
---|
326 | * be greater than the size requested for allocation. |
---|
327 | * Returns TRUE if the @a starting_address is in the heap, and FALSE |
---|
328 | * otherwise. |
---|
329 | * |
---|
330 | * @param[in] the_heap is the heap to operate upon |
---|
331 | * @param[in] starting_address is the starting address of the user block |
---|
332 | * to obtain the size of |
---|
333 | * @param[in] size points to a user area to return the size in |
---|
334 | * @return TRUE if successfully able to determine the size, FALSE otherwise |
---|
335 | * @return *size filled in with the size of the user area for this block |
---|
336 | */ |
---|
337 | boolean _Heap_Size_of_user_area( |
---|
338 | Heap_Control *the_heap, |
---|
339 | void *starting_address, |
---|
340 | size_t *size |
---|
341 | ); |
---|
342 | |
---|
343 | /** |
---|
344 | * This function tries to resize in place the block that is pointed to by the |
---|
345 | * @a starting_address to the new @a size. |
---|
346 | * |
---|
347 | * @param[in] the_heap is the heap to operate upon |
---|
348 | * @param[in] starting_address is the starting address of the user block |
---|
349 | * to be resized |
---|
350 | * @param[in] size is the new size |
---|
351 | * @param[in] old_mem_size points to a user area to return the size of the |
---|
352 | * user memory area of the block before resizing. |
---|
353 | * @param[in] avail_mem_size points to a user area to return the size of |
---|
354 | * the user memory area of the free block that has been enlarged or |
---|
355 | * created due to resizing, 0 if none. |
---|
356 | * @return HEAP_RESIZE_SUCCESSFUL if successfully able to resize the block, |
---|
357 | * HEAP_RESIZE_UNSATISFIED if the block can't be resized in place, |
---|
358 | * HEAP_RESIZE_FATAL_ERROR if failure |
---|
359 | * @return *old_mem_size filled in with the size of the user memory area of |
---|
360 | * the block before resizing. |
---|
361 | * @return *avail_mem_size filled in with the size of the user memory area |
---|
362 | * of the free block that has been enlarged or created due to |
---|
363 | * resizing, 0 if none. |
---|
364 | */ |
---|
365 | Heap_Resize_status _Heap_Resize_block( |
---|
366 | Heap_Control *the_heap, |
---|
367 | void *starting_address, |
---|
368 | size_t size, |
---|
369 | uint32_t *old_mem_size, |
---|
370 | uint32_t *avail_mem_size |
---|
371 | ); |
---|
372 | |
---|
373 | /** |
---|
374 | * This routine returns the block of memory which begins |
---|
375 | * at @a starting_address to @a the_heap. Any coalescing which is |
---|
376 | * possible with the freeing of this routine is performed. |
---|
377 | * |
---|
378 | * @param[in] the_heap is the heap to operate upon |
---|
379 | * @param[in] start_address is the starting address of the user block |
---|
380 | * to free |
---|
381 | * @return TRUE if successfully freed, FALSE otherwise |
---|
382 | */ |
---|
383 | boolean _Heap_Free( |
---|
384 | Heap_Control *the_heap, |
---|
385 | void *start_address |
---|
386 | ); |
---|
387 | |
---|
388 | /** |
---|
389 | * This routine walks the heap to verify its integrity. |
---|
390 | * |
---|
391 | * @param[in] the_heap is the heap to operate upon |
---|
392 | * @param[in] source is a user specified integer which may be used to |
---|
393 | * indicate where in the application this was invoked from |
---|
394 | * @param[in] do_dump is set to TRUE if errors should be printed |
---|
395 | * @return TRUE if the test passed fine, FALSE otherwise. |
---|
396 | */ |
---|
397 | boolean _Heap_Walk( |
---|
398 | Heap_Control *the_heap, |
---|
399 | int source, |
---|
400 | boolean do_dump |
---|
401 | ); |
---|
402 | |
---|
403 | /** |
---|
404 | * This routine walks the heap and tots up the free and allocated |
---|
405 | * sizes. |
---|
406 | * |
---|
407 | * @param[in] the_heap pointer to heap header |
---|
408 | * @param[in] the_info pointer to a status information area |
---|
409 | * @return *the_info is filled with status information |
---|
410 | * @return 0=success, otherwise heap is corrupt. |
---|
411 | */ |
---|
412 | Heap_Get_information_status _Heap_Get_information( |
---|
413 | Heap_Control *the_heap, |
---|
414 | Heap_Information_block *the_info |
---|
415 | ); |
---|
416 | |
---|
417 | /** |
---|
418 | * This heap routine returns information about the free blocks |
---|
419 | * in the specified heap. |
---|
420 | * |
---|
421 | * @param[in] the_heap pointer to heap header. |
---|
422 | * @param[in] info pointer to the free block information. |
---|
423 | * |
---|
424 | * @return free block information filled in. |
---|
425 | */ |
---|
426 | void _Heap_Get_free_information( |
---|
427 | Heap_Control *the_heap, |
---|
428 | Heap_Information *info |
---|
429 | ); |
---|
430 | |
---|
431 | #if !defined(__RTEMS_APPLICATION__) |
---|
432 | |
---|
433 | /** |
---|
434 | * A pointer to unsigned integer conversion. |
---|
435 | */ |
---|
436 | #define _H_p2u(_p) ((_H_uptr_t)(_p)) |
---|
437 | |
---|
438 | #include <rtems/score/heap.inl> |
---|
439 | |
---|
440 | /** |
---|
441 | * Convert user requested 'size' of memory block to the block size. |
---|
442 | * |
---|
443 | * @note This is an internal routine used by _Heap_Allocate() and |
---|
444 | * _Heap_Allocate_aligned(). Refer to 'heap.c' for details. |
---|
445 | * |
---|
446 | * @param[in] size is the size of the block requested |
---|
447 | * @param[in] page_size is the page size of this heap instance |
---|
448 | * @param[in] min_size is minimum size block that should be allocated |
---|
449 | * from this heap instance |
---|
450 | * |
---|
451 | * @return This method returns block size on success, 0 if overflow occured. |
---|
452 | */ |
---|
453 | extern size_t _Heap_Calc_block_size( |
---|
454 | size_t size, |
---|
455 | uint32_t page_size, |
---|
456 | uint32_t min_size |
---|
457 | ); |
---|
458 | |
---|
459 | /** |
---|
460 | * This method allocates a block of size @a alloc_size from @a the_block |
---|
461 | * belonging to @a the_heap. Split @a the_block if possible, otherwise |
---|
462 | * allocate it entirely. When split, make the lower part used, and leave |
---|
463 | * the upper part free. |
---|
464 | * |
---|
465 | * This is an internal routines used by _Heap_Allocate() and |
---|
466 | * _Heap_Allocate_aligned(). Refer to 'heap.c' for details. |
---|
467 | * |
---|
468 | * @param[in] the_heap is the heap to operate upon |
---|
469 | * @param[in] the_block is the block to allocates the requested size from |
---|
470 | * @param[in] alloc_size is the requested number of bytes to take out of |
---|
471 | * the block |
---|
472 | * |
---|
473 | * @return This methods returns the size of the allocated block. |
---|
474 | */ |
---|
475 | extern uint32_t _Heap_Block_allocate( |
---|
476 | Heap_Control* the_heap, |
---|
477 | Heap_Block* the_block, |
---|
478 | uint32_t alloc_size |
---|
479 | ); |
---|
480 | |
---|
481 | /* |
---|
482 | * Debug support |
---|
483 | */ |
---|
484 | |
---|
485 | #if defined(RTEMS_DEBUG) |
---|
486 | #define RTEMS_HEAP_DEBUG |
---|
487 | #endif |
---|
488 | |
---|
489 | /** |
---|
490 | * We do asserts only for heaps with instance number greater than 0 assuming |
---|
491 | * that the heap used for malloc is initialized first and thus has instance |
---|
492 | * number 0. Asserting malloc heap may lead to troubles as printf may invoke |
---|
493 | * malloc thus probably leading to infinite recursion. |
---|
494 | */ |
---|
495 | #if defined(RTEMS_HEAP_DEBUG) |
---|
496 | #include <assert.h> |
---|
497 | |
---|
498 | #define _HAssert(cond_) \ |
---|
499 | do { \ |
---|
500 | if(the_heap->stats.instance && !(cond_)) \ |
---|
501 | __assert(__FILE__, __LINE__, #cond_); \ |
---|
502 | } while(0) |
---|
503 | |
---|
504 | #else /* !defined(RTEMS_HEAP_DEBUG) */ |
---|
505 | |
---|
506 | #define _HAssert(cond_) ((void)0) |
---|
507 | |
---|
508 | #endif /* !defined(RTEMS_HEAP_DEBUG) */ |
---|
509 | |
---|
510 | #endif /* !defined(__RTEMS_APPLICATION__) */ |
---|
511 | |
---|
512 | #ifdef __cplusplus |
---|
513 | } |
---|
514 | #endif |
---|
515 | |
---|
516 | /**@}*/ |
---|
517 | |
---|
518 | #endif |
---|
519 | /* end of include file */ |
---|